Richard Thomas, who played “John Boy” on “The Waltons” in the ’70s, has his own talented boy, Montana, 13. “Project Runway” star Tim Gunn lunched with Thomas and his family at Sardi’s the other day before Richard’s matinee of “Race.” After talking to fashion wunderkind Montana, Gunn de clared, “I’ve found my mini- me.” Gunn’s Parsons colleague, associate chair Carmela Spin elli, put the luncheon together after she saw some of Mon tana’s sketches. “He has more passion and innate talent than many of the students Tim and I taught over the years,” she said.